Yücel Erk

A new experimental hypertrophic scar model in guinea pigs.

Many aspects of the biology and effective therapy of proliferative scars remain undefined, in part due to a lack of an accurate, practical, reproducible, and economical animal model for systematically studying hypertrophic scars. This study was designed to investigate whether hypertrophic scar formation could be induced in guinea pigs by removal of the panniculus carnosus alone, and by a combination of the removal of the panniculus carnosus with application of coal tar afterwards. Whole thickness skin excision or deep partial thickness injury was used to create the lesions on intact skin. Different anatomic locations were tested in different groups. Scars thus developed were examined morphologically by light microscopy and electron microscopy (TEM and SEM) and biochemically by measuring the activity of glucose-6-phosphate dehydrogenase (G6PD) to check whether these scars had morphological and biochemical properties specific to hypertrophic scars. The albino guinea pigs used in this study were divided into three groups. Removal of the panniculus carnosus was performed from the ventral aspect of the torso in animals in groups I and II. On the skin overlying the area of panniculectomy, circular skin excision was performed in group I, and deep partial thickness burn injury was inflicted in group II, to see whether wounds would heal with hypertrophic scars. In group III, dorsal aspect of the torso were used and wounds were produced by circular skin excisions followed by panniculectomy on both sides but coal tar was applied to only one side. Tissue samples were taken from the scars that were hypertrophic in appearance, and from normal scars and normal skin for comparison. Light and electron microscopic examinations and G6PD activity measurements were performed on these samples. While hypertrophic scar development was not seen in group I and group II, scars with morphological and biochemical properties specific to hypertrophic scars developed in one third of animals in group III after healing of the wounds treated with coal tar. In conclusion, it is shown that it is possible to develop experimental hypertrophic scars in guinea pigs with morphological and biochemical properties similar to those of human proliferative scars. Therefore this model is a new, practical, and economical experimental animal model to study proliferative scars, although improvements are needed to increase yield.

Reconstruction of postburn breast deformities

Postburn breast deformity is a sequela of severe scar contraction of the burned chest. During the past 3 years, 24 female patients with such deformities required reconstruction, the surgery was performed in our department. These patients, the types of the deformities and the techniques used for reconstruction have been reviewed. For mild deformities (10 patients) reconstructions with skin grafts and local skin flaps were found to be satisfactory. For deformities which affected the mammary development (14 patients), mammary prostheses directly or under the soft tissue obtained by skin expansion or musculocutaneous flaps were used. In three of our patients, reduction mammaplasty or mastopexy was needed to symmetrize the breasts.

Semicircular lipoatrophy after intragluteal injection of benzathine penicillin

A 3-year old girl had localized lipoatrophy after an intragluteal injection of benzathine penicillin G. No associated abnormalities were found.

Repeated mandibular lengthening in Treacher Collins syndrome: a case report

A patient with mandibular hypoplasia associated with Treacher Collins syndrome was treated by bilateral distraction osteogenesis. Since less than optimal length was provided by the first distraction, a second corticotomy was performed in the newly formed bone 6 months after the first distraction. Thus bone gained by distraction osteogenesis was subjected to distraction once again. New bone formation occurred after the second lengthening. This case illustrated that distraction osteogenesis may be applied to the mandible at the site of previous distraction.

A new flap model in rats: iliac osteomusculocutaneous flap.

Although osteomusculocutaneous flaps are used frequently in clinical practice to repair defects involving soft tissue and bone, there are still many questions that remain to be answered regarding their basic physiology. To accomplish such basic science studies, simple and reliable animal osteomusculocutaneous flap models are needed. The purpose of this study was to describe a new flap model in rats—namely, the iliac osteomusculocutaneous flap. Thirty adult Wistar rats weighing 200 to 250 g were used in this experiment. In 15 rats, the vascular anatomy of the iliolumbar vessels and their relation with adjacent soft tissues and the iliac bone was determined by anatomic dissection. Based on this anatomic study, the iliac osteomusculocutaneous flap model was created in rats. The flap is comprised of a skin island (3 × 3 cm) in the flank region, a 1 × 1-cm segment of iliac bone, and an abdominal wall muscle cuff. In 10 rats, the flap was raised as an island flap based on its vascular pedicle of iliolumbar vessels, and was replaced in situ. In the remaining 5 rats, the flap was transferred to the groin region as a free flap. Direct observation on postoperative day 7 revealed that the skin island of all the flaps was completely viable. Bone scintigraphy performed on postoperative day 3 in free flaps demonstrated radionuclide uptake, indicating viability of the bony segment. The dye injection study revealed ink staining within blood vessels of the bone, confirming its viability. Microangiography of the flap demonstrated vascularity of each component of the flap by the iliolumbar vessels, including a distinct branch to the iliac bone. The authors conclude that the iliac osteomusculocutaneous flap of the rat is a simple and reliable flap model that offers the following advantages: (1) It is a true osteomusculocutaneous flap, (2) it can be used as a free flap without the need for an isogeneic rat, (3) the vascular pedicle is consistent, and (4) it is harvested from a small-animal species.

Effect of slow-release 5-Fluorouracil on capsule formation around silicone breast implants: an experimental study with mice.

BackgroundCapsule formation around breast implants, development of tendon adhesions after tendon repair, intestinal brits after laparatomies, hypertrophic scars in skin incisions all are the results of excessive collagen synthesis to the extracellular matrix by fibroblasts. Any intervention that leads to cessation of collagen synthesis in these clinical situations may help to prevent these untoward results of wound healing. Although 5-fluorouracil (5-FU) is used mainly as a cytotoxic drug in chemotherapy protocols, it decreases cellular metabolism and blocks protein synthesis only at lower concentrations. Findings have shown that 5-FU downregulates fibroblast proliferation and differentiation in vitro. It has been used to treat fibroproliferative disorders of the eye and skin and is thought to inhibit thymidylate synthetase, blocking DNA replication.MethodsThis study used five treatment groups: (1) gelatin only, (2) silicone only, (3) silicone + gelatin, (4) silicone + gelatin containing 1 mg of 5-FU, and (5) silicone + gelatin containing 5 mg of 5-FU. The release kinetics of 5-FU from gelatin have been investigated by means of ultraviolet spectrophotometric analysis. Specimens were obtained on postoperative day 30. Gross evaluation and histopathologic examination were conducted for capsule formation and the development of inflammation.ResultsThe silicone group had the most prominent capsule formation among all the groups. The gelatin group was second, and the silicone + gelatin group was third. As compared with the other groups, the 5-FU–containing groups had the least capsule formation. The 5-mg 5-FU–containing group had the most inflammation. The silicone + gelatin group was second in inflammation. Although the silicone, gelatin, and 1-mg 5-FU–containing groups had the same means, the results of the silicone group showed the most divergent data within the group.ConclusionsBecause 5-FU loaded to a gelatin carrier for its slow release seems to prevent capsule formation around silicone blocks, it may be used to prevent capsule formation around silicone breast implants.

Malignant melanoma in xeroderma pigmentosum patients: report of five cases

Xeroderma pigmentosum is a rare genetic disease transmitted via a recessive gene with an altered reaction of the epidermis to light. Fifty per cent of patients develop a skin tumour by 8 years of age. The majority of patients may have multiple tumours, but metastasis is rare. In the last 25 years we have treated 24 xeroderma pigmentosum patients in our clinic. Only five patients had developed cutaneous malignant melanoma during their follow-up. Three of the patients were from the same family, melanoma occurring in three of five affected individuals. All xeroderma pigmentosum patients with malignant melanoma had received classical treatment modalities. Except one case of fulminant pattern, all four patients had long disease-free survival. Although early detection and treatment of these cutaneous malignancies will reduce morbidity and mortality, genetic counselling remains the most important protective measure for xeroderma pigmentosum.

Intrasphenoidal migration of a premaxillary Kirschner wire.

OBJECTIVE The use of Kirschner wire for the fixation of premaxilla is a well-known method in bilateral cleft lip surgery. We report a case in which the Kirschner wire of the premaxillary fixation had migrated intrasphenoidally. RESULTS AND CONCLUSIONS The foreign body was accidentally discovered during a cephalometric analysis and was taken out surgically through an upper lip sulcus incision. Although the wire remained asymptomatic for 10 years, it constituted a potential danger for intracranial migration.

Bartsocas-Papas syndrome with fusion of the lips and posterior fusion defects of the thoracic vertebrae.

Bartsocas-Papas syndrome is a rare popliteal pterygial syndrome with multiple anomalies including microcephaly, facial clefts, filiform bands, ankyloblepharon, syndactyly, and other ectodermal anomalies. Affected infants usually die perinatally. The authors present an 8-month-old female infant with manifestations of this syndrome and some additional traits including fusion of the lips, intraoral filiform bands, alopecia totalis, and posterior fusion failure of the vertebrae. The fused lips were opened by incising the fibrotic bands closing her mouth. Details of this patient and a brief review of the literature is presented.

Comparison of immune response to nerve allograft segments in fetal and adult rabbits: a histological study.

&NA; Fetuses, as opposed to adults, are immature immunologically and it has been proved that they can tolerate allograft materials much better than adults. In this study the rejection phenomenon of nerve allografts was compared histologically in fetuses and adults. The study was performed in 60 New Zealand rabbits (30 pregnant and 30 nonpregnant), and allograft nerve segments were obtained from Chinchilla rabbits. The animals were divided into fetal and adult groups. Each group was studied at various time periods. Nerve allografts were placed under the panniculus carnosus in the interscapular region of the fetuses and adults. In both fetal and adult groups, the nerve allograft segments were assessed histologically after 1, 7, and 30 days. The criteria used during the evaluation were the degenerative findings in the myelinated axons (large, medium, and small axons), changes in Schwanns cells, and the quantity of infiltrating cells. The changes were graded microscopically from 0 (no change) to 3 (severe destruction and cellular infiltration). Cellular infiltration was more extensive in the adult groups than in the fetal groups. Earlier fetal groups showed minimal infiltration, but the response became more extensive in the later fetal groups. This is probably related to the removal of the fetuses from their intrauterine environment. When comparing fetal and adult groups, the results were significant (p < 0.05). The fetuses tolerated the nerve allograft segments better than the adults. This may be related to the immature immune system of the fetuses. Ağaoğlu G, Kayikçioğlu A, Sargon M, Erk Y, Mavili E. Comparison of immune response to nerve allograft segments in fetal and adult rabbits: a histological study. Ann Plast Surg 2000;43:398‐404